.menu {
  width: 120px;
  height: 100%;
  text-align: center;
  color: #4b646f;
  background: #1a2226;
}

.menu .desc {
  padding: 10px;
}

.menu li {
  padding: 0 20px;
  line-height: 40px;
  position: relative;
  text-align: left;
  color: #b8c7ce;
  cursor: pointer;
  white-space:nowrap;
}

.menu li a {
  display: block;
  color: #b8c7ce;
  text-decoration: none;
}

.menu li:hover,
.menu li:hover > a {
  color: #ffffff;
}

.menu li,
.menu li > span,
.menu li > a,
.menu li > a > span {
  background-color: #2a3236;
}

.menu li:hover,
.menu li:hover > span,
.menu li:hover > a,
.menu li:hover > a > span {
  background-color: #1e282c;
}

.menu li > ul {
  display: none;
  position: absolute;
  left: 100%;
  top: 0;
}

.menu li:hover > ul {
  display: block;
  animation: menu-show 0.5s;
  -moz-animation: menu-show 0.5s;	/* Firefox */
  -webkit-animation: menu-show 0.5s;	/* Safari 和 Chrome */
  -o-animation: menu-show 0.5s;
}

@keyframes menu-show {
  from {opacity: 0;}
  to {opacity: 1;}
}

@-moz-keyframes menu-show /* Firefox */
{
  from {opacity: 0;}
  to {opacity: 1;}
}

@-webkit-keyframes menu-show /* Safari 和 Chrome */
{
  from {opacity: 0;}
  to {opacity: 1;}
}

@-o-keyframes menu-show /* Opera */
{
  from {opacity: 0;}
  to {opacity: 1;}
}

.menu li.more:after {
  font-family: 'icomoon' !important;
  speak: none;
  font-style: normal;
  font-weight: normal;
  font-variant: normal;
  text-transform: none;
  line-height: 1;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  content: '\ea1c';
  width: 0;
  display: inline-block;
  font-size: 14px;
}

@media (max-width: 800px) {
  .menu {
    width: 50px;
  }
  .menu .desc {
    padding: 10px 5px;
  }
  .menu li {
    min-width: 100px;
  }
  .menu nav > ul > li {
    padding: 0;
    text-align: center;
    min-width: 50px;
    width: 50px;
  }
  .menu nav > ul > li > span,
  .menu nav > ul > li.more:after,
  .menu nav > ul > li > a > span {
    display: none;
  }

  .menu li:hover > span,
  .menu li:hover > a > span {
    display: block;
    position: absolute;
    left: 50px;
    top: 0;
    width: 100px;
    padding: 0 20px;
    text-align: left;
  }

  .menu li:hover > ul {
    top: 40px;
  }

  .menu li li:hover > ul {
    top: 0;
  }

}
